Changed index.html over to using a html import to get lcars. this means lcars can add new files and the html file doesn't have to change - just the template!

Signed-off-by: Martin Evans <martindevans@gmail.com>
Added a say-hi custom element

Signed-off-by: Martin Evans <martindevans@gmail.com>
Implemented root Lcars container and Lcars columns as custom elements:
 - modified elbows-demo.html (our simplest page) to use as many custom elements as possible)
 - Removed experimental hi.template
 - Entirely done away with the template system, it sucked. Moved definitions for custom elements into ts files (could possibly do with using imported html templates for more complicated custom elements).
 - Moved external dependencies into lcats.template, this means that all you need to do to get lcars and all dependencies is <link rel="import" href="build/html/lcars-templates.html"> in the head!
 - Implemented a registerCustomLcarsElement function, which handles a lot of the boilerplate for custom elements

Signed-off-by: Martin Evans <martindevans@gmail.com>
Merge pull request #38 from martindevans/feature/html-import

Feature/html import